First dam removal in Latvia in one of the most productive salmonid rivers in the Baltic Sea region


The River Norina

River Norina runs through the Salaca Valley Nature Park in north-central Latvia (Figure 1), is ~11 km long, and is a left-bank tributary of River Salaca that flows into the Gulf of Riga. The Salaca Valley Nature Park has been established to preserve the habitat types of protected species, several of which are included in the EU Habitats Directive, and the landscape diversity of the valley.

Figure 1. Location of River Norina at north-central Latvia (indicated by the blue dot)

The ecological functions of River Norina used to be disrupted due to fragmentation. More specifically, an old wooden dam, that used to power a watermill, was fragmenting its longitudinal connectivity for ~100 years. It was located about 1 km from the confluence of River Norina and River Salaca (latitude: 57.827768; longitude: 24.487384; Figure 2). That barrier was hindering the migration of salmonid species and lamprey to suitable spawning grounds that have been recorded upstream the dam.

Figure 2. River Norina and the location of the wooden dam (indicated by the blue dot)

The ecological functionality of River Norina was aggravated by beaver activity in the lower reach of the river and its former mill pond. Beavers had caused log jams (Figure 3) and created unsurpassable conditions for fish migration. The disrupted natural water flow resulted in coastal erosion and hindered sedimentation processes, which had adverse impact on the quality and functionality of River Norina.

Figure 3. Log jam at River Norina (photo by Latvian Fund for Nature)

Barrier removal

In autumn 2015 a part of River Norina was restored, from the former mill to the mouth of the River Salaca. Specifically, the old wooden dam was demolished (Figure 4, Video 1) and cleanup of the river and the riverbanks was performed, attended by representatives of the Latvian Fund for Nature and the Nature Protection Board. Restoration works ended on October 15 (Figures 5-6).  

Figure 4. Removal works of the wooden dam at River Norina (photo by Latvian Fund for Nature)
Figure 5. River Norina site after the removal of a log jam (photo by Latvian Fund for Nature)
Figure 6. Removal site after the demolition of the wooden dam at River Norina (photo by Latvian Fund for Nature)

Since the dam was private property, an agreement was achieved beforehand with the owner. Restoration works were organized by the Latvian Fund for Nature in close cooperation with North Vidzeme Biosphere reserve and supervised by river restoration experts. The activity was supported by EKOenergy’s Environmental Fund; and the total cost of the project was 4000 Euro.

Video 1. River restoration and removal works of the wooden dam at River Norina (video by “Vides Fakti”, LTV1)

Before & After photo pair

River Norina before (left) and after (right) the removal of logs (photos by Latvian Fund for Nature)

Written by Foivos A. Mouchlianitis

  • Name: Norina River dam
  • Location: River Norina, Salaca Valley Nature Park, Latvia
  • Type: dam
  • Dimension: Height ~1 m; Length ~5 m
  • Aims of removal: restoration of fish migration
  • Year of removal: 2015